Variations in Entrance of Vertebral Artery in Korean Cervical Spine: MDCT-based Analysis

Embryology of the vertebral artery and variants of the adult

The vertebral arteries represent in the adult the main blood supply of the posterior cranial fossa, even if they appear relatively late during the embryological life. We reviewed all the most important steps of the vertebral artery's embryological development and the most common variants that can occur in the adult. The aim of this review is to summarize the main events of the development of this artery and to give an embryological explication for the most common variants of this artery.

The Vertebral Artery: A Systematic Review and a Meta-Analysis of the Current Literature

(1) Background. The anatomical variations of the vertebral arteries (VAs) have a significant impact both in neurosurgery and forensic pathology. The purpose of this study was to evaluate the variational anatomy of the vertebral artery. We evaluated anatomical aspects regarding the V1 and V2 segments of the VA: origin, course, tortuosity, hypoplasia, and dominance, and established the prevalence of each variation. (2) Methods. We conducted a systematic search in PubMed and Google Scholar databases, up to December 2022. Sixty-two studies, comprising 32,153 vessels, were included in the current meta-analysis. We used a random-effects model with a DerSimonian-Laird estimator. The confidence intervals were set at 95%. The heterogeneity between studies was assessed using I². The funnel plot and Egger's regression test for plot asymmetry were used for the evaluation of publication bias. Statistical significance was considered at p < 0.05. (3) Results. The most common site for the origin of both VAs was the subclavian artery. The aortic arch origin of the left VA had a prevalence of 4.81%. Other origins of the right VAs were noted: aortic arch (0.1%), right common carotid artery (0.1%), and brachiocephalic trunk (0.5%). Ninety-two percent of the VAs entered the transverse foramen (TF) of the C6 vertebra, followed by C5, C7, C4, and least frequently, C3 (0.1%). Roughly one out of four (25.9%) VAs presented a sort of tortuosity, the transversal one representing the most common variant. Hypoplasia occurred in 7.94% of the vessels. Left VA dominance (36.1%) is more common, compared to right VA dominance (25.3%). (4) Conclusions. The anatomy of the VA is highly irregular, and eventual intraoperative complications may be life-threatening. The prevalence of VA origin from the subclavian artery is 94.1%, 92.0% of the VAs entered the TF at C6, 26.6% were tortuous, and 7.94% were hypoplastic.

Cervical rotational osteotomy for correction of axial deformity in a patient with ankylosing spondylitis

PURPOSE

Severe cervical axial deformity associated with ankylosing spondylitis (AS) is rare in clinic, and there are little concerns about surgical treatment of axial deformity associated with AS. The case study aims to show the surgical technique to perform cervical rotational osteotomy.

METHODS

We present the case of a young AS patient whose neck was fixed in a left-rotational posture at 18°, requiring his trunk to be turned to the right to look forward visually. This made his gait appear to be limping, inconveniencing him with great difficulty. In order to correct this deformity, we performed a novel cervical rotational osteotomy through a one-stage posterior-anterior-posterior approach. Firstly, we performed laminectomies of C7 and T1, followed by a C7/T1 facetectomy with release of the bilateral C8 nerve roots. Next, we performed C7/T1 discectomy, bony resection of the lateral body and uncovertebral joints. The head of the patient was then rotated manually, so that both his face and torso were simultaneously facing frontward. Finally, rods spanning the screws from C6 to T2 were fixed.

RESULTS

Postoperatively, the patient's axial malalignment was significantly improved, and he was able to walk normally. Surgical outcomes were well maintained at a 3-year follow-up.

CONCLUSION

Through this case, we hope to draw the attention to spinal axial deformity and provide a reference point in the surgical treatment of spinal axial deformity.

Entrance and origin of the extracranial vertebral artery found on computed tomography angiography

To investigated morphological variability of vertebral artery (VA) origin and its entrance level into cervical transverse foramina by computed tomography angiography (CTA). To retrospectively investigated CTA of 223 subjects (446 VA courses). Investigated were origin of the VA and its level of entrance into vertebral transverse foramen with notification of the sex and side of variation. The VA entered the C6 transverse process in 91.70% of specimens (409 out of 446 VA courses). Abnormal entrance of VA was observed in 8.30% of specimens (37 VA courses), with the level of entrance into the C3, C4, C5, or C7 transverse foramen at 0.22%, 2.47%, 4.71% and 0.90% respectively. Comparably, the overall variability of abnormal origin of VA was 1.57% (7 out of 466 VA courses), in which the left vertebral arteries all arose from aortic arch. The variation rate of vertebral entrance rose up to 50% in abnormal origin subgroup. When comparing subgroups of subjects with normal and abnormal origin, there was significance difference in the frequency of entrance variation in the level of transverse foramen (p < 0.001). Abnormal entrance and origin of VA were observed in 8.30% and 1.57% of VA courses, which can be accurately appeared by CTA. Regarding to the subgroups of abnormal origin, the frequency of entrance variation was significantly increased in the level of transverse foramen compared to that of normal origin.

Accidente cerebrovascular isquémico de la arteria cerebral media

La segunda causa de muerte a nivel mundial corresponde a los ataques cerebrovasculares (ACV), de los cuales más de dos terceras partes son de origen isquémico. Causan discapacidad a largo plazo por lo que conocer la anatomía de la circulación cerebral y las posibles manifestaciones clínicas del ACV isquémico permite sospechar, diagnosticar y brindar un manejo oportuno y apropiado, reduciendo el impacto en la salud y la calidad de vida del paciente y sus cuidadores. Objetivo: relacionar los últimos hallazgos en la anatomía arterial cerebral, los mecanismos fisiopatológicos y las manifestaciones clínicas del ACV isquémico de la arteria cerebral media (ACM). Materiales y métodos: revisión de la literatura mediante la búsqueda con términos MeSH en la base de datos Medline, incluyendo estudios, ensayos y metaanálisis publicados entre 2000 y 2020 en inglés y español, además de otras referencias para complementar la información. Resultados: se seleccionaron 59 publicaciones, priorizando la de los últimos 5 años y las más relevantes del rango temporal consultado. Conclusiones: son escasos los estudios sobre la presentación clínica de los ACV, lo que sumado a la variabilidad interindividual de la irrigación cerebral, dificulta la determinación clínica de la localización de la lesión dentro del lecho vascular. La reperfusión del área de penumbra isquémica como objetivo terapéutico se justifica por los mecanismos fisiopatológicos de la enfermedad.

Atypical Course of Vertebral Artery Outside the Cervical Spine: Case Report and Review of the Literature

BACKGROUND

The vertebral arteries are branches of the subclavian arteries supply blood to the posterior part of the encephalon, forming vertebrobasilar circulation. Disorders of vertebrobasilar circulation have significant clinical implications. Symptoms of these disorders include dizziness, vomiting, collapse, vision and cerebellar disorders. The vertebral artery usually ascends in the transverse foramina of the cervical vertebrae to reach the posterior cranial cavity by entering the magnum foramen. Although most often the vertebral artery enters the C6 transverse process, anatomic variation may occur.

CASE DESCRIPTION

In this case, a 16-year-old male patient with casuistic anatomic variant of vertebral artery course is described. In this case report, left vertebral artery ascended outside the transverse foramina of cervical vertebrae C6-C3 and entered transverse foramen of axis. The patient suffered from collapse and dizziness during neck and head movements as a result of arterial folding. After rehabilitation and posture and proper movement learning, the frequency of symptoms subsided.

CONCLUSIONS

Variability of the vertebral arteries may have clinical implications, and knowledge of its topography is important for mechanism of vertebrobasilar circulatory disorder understanding and for surgical approach to the cervical spine and neck anatomic structures.

Anatomy of scalenovertebral triangle: A vade mecum for clinicians

OBJECTIVE OF THE STUDY

The thorough anatomical knowledge of scalenovertebral triangle or Triangle of the vertebral artery and its contents is crucial in various neurosurgical procedures such as scalenotomy, stellate ganglion block, direct isolation of proximal vertebral artery and proximal brachial plexus repair.

MATERIAL AND METHOD

Thirty scalenovertebral triangles of known age and sex were dissected. The morphometry of the triangle and stellate ganglion was done. Various relevant distances were measured for topographical location of neurovascular structures especially stellate ganglion and vertebral artery within the triangle.

RESULTS

The mean height and width of the scalenovertebral triangle was 21.7+5.1mm and 19.4+4.4mm respectively. Vertebral artery originated from subclavian artery within the triangle except in one case (left side) where it originated from aortic arch. The mean minimum distance of stellate ganglion from phrenic nerve, scalenus anterior and vertebral origin was 12.6+4.5mm, 12.26+4mm and 2.3+1.3mm respectively.

CONCLUSIONS

The origin and proximal part of vertebral artery may not be present within the scalenovertebral triangle, thus topographic anatomy of the stellate ganglion is also affected and may cause complications during stellate ganglion block. Stellate ganglion is never located in the lateral or upper third of triangle. Occasionally, the phrenic nerve may cross the triangle, making it unsafe during stellate ganglion block.

Tonic-clonic seizure during the ultrasound-guided stellate ganglion block because of an injection into an unrecognized variant vertebral artery: A case report

RATIONALE

Recent years have witnessed a marked improvement in the safety and accuracy of nerve blocks with the help of ultrasound and other visualization technologies. This study reports a challenging case of a severe complication during the ultrasound-guided stellate ganglion block.

PATIENT CONCERNS

A 28-year-old male patient with refractory migraine complained episodic pulsatile pain with photophobia, haphalgesia of the scalp for 3 years.

INTERVENTIONS

Ultrasound-guided stellate ganglion block with 4 ml of 1% lidocaine was administrated.

OUTCOMES

A sudden loss of consciousness and tonic-clonic seizure was occurred after negative aspiration and test dose. Further sonographic examination revealed a variation in the left vertebral artery, which remained unrecognized during the needle insertion because of its sliding ability under the differential pressure applied by the probe.

LESSONS

Inadvertent intra-arterial injection of a local anesthetic agent could be minimized under the ultrasound guidance with various protective strategies, including the determination of any prior variation, optimizing the block route, maintaining a constant probe pressure, and using saline for the test dosage. This case resulted in the implementation of new protocols of the ultrasound-guided stellate ganglion block in our department.

A case involving a giant aberrant craniocervical arteriovenous malformation

Background:

Spinal cord arteriovenous malformations (AVMs) comprise about 3%–4% of primary intraspinal masses and are only rarely found external to the C2–C7 cervical vertebral foramen.

Case Description:

A 21-year-old female presented with neck pain and a spastic quadriparesis of 1 year duration. The cervical magnetic resonance imaging and three-dimensional computed tomography angiograms documented an AVM/dural arteriovenous fistula on the right fed by multiple arteries located in the C5–C6 and C6–C7 foramen intervertebralis; utilizing a laminectomy, the large feeding arteries were double-clipped. This allowed for devascularization of the AVM and facilitated resection while preserving the aberrant vertebral artery. The patient was discharged within 1 week and, 2 months later, was able to ambulate to the outpatient clinic.

Conclusion:

Double clipping of the two main right-sided arterial feeders at the C5–C6 and C6–C7 levels allowed for devascularization and resection of this large cervical AVM while carefully preserving the aberrant vertebral artery.

New Optimal Needle Entry Angle for Cervical Transforaminal Epidural Steroid Injections: A Retrospective Study

Objective: A cervical epidural steroid injection is one of the most commonly performed interventions to manage chronic neck pain and cervical radiculopathy. Despite its many severe complications, cervical transforaminal epidural steroid injection (CTFESI) is a clinically necessary modality for managing neck pain and cervical radiculopathy. We aimed in this study to find a safer optimal needle entry angle to decrease the chance of an accidental vertebral artery (VA) puncture even with a proper needle entry angle and to visualize the target of the needle tip. Methods: This retrospective study included 312 patients with neck pain or cervical radiculopathy who had undergone magnetic resonance imaging scans for diagnosis and treatment. The first line was drawn from the midpoint of the two articular pillars and passed through the exact midline of the spinous process. The second line was drawn parallel to the ventral lamina line (conventional transforaminal approach line, CTAL). The third line was drawn parallel to the ventral margin at the midpoint of the superior articular process's ventral border (new transforaminal approach line, NTAL). The angle of intersection between the midline and CTAL versus with NTAL were measured from both sides (right and left) at C5-6, C6-7, and C7-T1 levels. Also, the distance of CTAL and NTAL from VA were measured from both sides at each level. We examined whether the CTAL and NTAL would penetrate the ipsilateral VA, internal carotid artery (ICA), and internal jugular vein (IJV). Results: There were significant differences between CTAL and NTAL angles at all levels (P < 0.001). There were significant differences between the distance of CTAL and NTAL from VA at all levels (P < 0.001). There were also significant differences between the observed frequency of CTAL and NTAL that would penetrate the major ipsilateral vessel (VA, ICA, and IJV) on all levels and sides (P < 0.001~0.030). Conclusion: The angle of NTAL (approximately 70°) is safer than the angle of CTAL (approximately 50°) when considering vascular injuries to vessels, such as the VA, ICA, and IJV.

Complications following US-guided core-needle biopsy for thyroid lesions: a retrospective study of 6,169 consecutive patients with 6,687 thyroid nodules

OBJECTIVES

To present the various complications of ultrasound (US)-guided core needle biopsy (CNB) of thyroid lesions in a large patient series.

METHODS

From January 2008 to March 2013, 6,169 patients underwent US-guided CNB of 6,687 thyroid nodules at a single institution. We assessed the number and types of major and minor complications, and evaluated the factors associated with complications.

RESULTS

Overall, 53 complications were observed in 50 patients (0.81 %), including 4 major and 49 minor complications. The major complications were massive haematoma (n = 2), pseudoaneurysm (n = 1) and voice change leading to disability that lasted for more than 30 days (n = 1). The minor complications were small to moderate haematoma (n = 42), carotid injury (n = 2), voice change that recovered within 30 days (n = 3), tracheal puncture (n = 1) and dysphagia (n = 1). Oedema (n = 12), vertebral puncture (n = 3) and vasovagal reaction (n = 1) were recorded as side effects. The presence of a coprocedure was the only significant factor associated with complications after thyroid CNB (P = 0.023).

CONCLUSIONS

US-guided CNB of thyroid lesions was found in a large population to be a safe procedure with a low complication rate.

KEY POINTS

• The complication rate after US-guided CNB for thyroid lesions was 0.81 % (50/6,169). • The rate of major complications was 0.06 % (4/6,169). • Vascular injury was the most common complication (47/6,169; 0.76 %). • None of the patients experienced permanent problems resulting from complications.

A New MRI Grading System for Cervical Foraminal Stenosis Based on Axial T2-Weighted Images

OBJECTIVE

The purpose of this study was to evaluate the reliability of a new magnetic resonance imaging (MRI) grading system for cervical neural foraminal stenosis (NFS).

MATERIALS AND METHODS

Cervical NFS at bilateral C4/5, C5/6, and C6/7 was classified into the following three grades based on the T2-weighted axial images: Grade 0 = absence of NFS, with the narrowest width of the neural foramen greater than the width of the extraforaminal nerve root (EFNR); Grade 1 = the narrowest width of the neural foramen the same or less than (but more than 50% of) the width of the EFNR; Grade 2 = the width of the neural foramen the same or less than 50% of the width of the EFNR. The MRIs of 96 patients who were over 60 years old (M:F = 50:46; mean age 68.4 years; range 61-86 years) were independently analyzed by seven radiologists. Interobserver and intraobserver agreements were analyzed using the percentage agreement, kappa statistics, and intraclass correlation coefficient (ICC).

RESULTS

For the distinction among the three individual grades at all six neural foramina, the ICC ranged from 0.68 to 0.73, indicating fair to good reproducibility. The percentage agreement ranged from 60.2% to 70.6%, and the kappa values (κ = 0.50-0.58) indicated fair to moderate agreement. The percentages of intraobserver agreement ranged from 85.4% to 93.8% (κ = 0.80-0.92), indicating near perfect agreement.

CONCLUSION

The new MRI grading system shows sufficient interobserver and intraobserver agreement to reliably assess cervical NFS.